Nptthod op



y 1949. L.' P. c. J. DUDLEY 2,468,963

' METHOD OF AND MEANS FOR MAKING STEREOSCOPIC X-RAY PHOTOGRAPHS FiledMarch 30, 1944 2 Sheets-Sheet 1 \mxmmmms I nuentor 4 PCJIDz/PLE L. P. C.J. DUDLEY METHOD OF AND MEANS FOR MAKING STEREOSCOPIC May 3, 1949.

X-RAY PHOTOGRAPHS 2 Sheets-Sheet 2 Filed March 50, 1944 nven tor -CIDapAttorneys Patented May 3, 1 949 I o N roR em S'TERE'OSCOPIC ".X-RAYPHOTGGRA'PHS Leslie Peter Clarence Jackpu'dley, Twick'enham,

England, a'ssignor to Stereoptics l'fiimited, London, England, aBritishcompany Application March 30,. 1944, Serial No. "528,724

In Great Britain March '26, 1943 Section L'PubIic Law-690, August 8,1946Patentexpires March 26, 1963 12 Claims. (Cl. 250 62) This inventionrelates to improvements in or toprovide a method whereby theaforesaid-di irelating to methods of and means for making ficulties maybe entirely avoided ;anda-further stereoscopic X-ray photographs, knownin the object'is to provide simple and efficientapparaart asstereoscopic radiographs, of the integral tus with the aid f which suchmethod can be :or parallax .panoramagram type and of the carried out. Ik L 4 parallax stereogram type. According to one feature of thepresentinven- In previously suggested methods of -making tion there isprovided a method o'fmaking stereostereoscopic radiographs a'grid isinterposed bescopic radi'ographs wherein a suitable "grid isintween thebody being subjected to X'-radi-ati0n terposed between the body beingsubjected to and a sensitized film or plate and the source 1'X-radiati'on and the sensitizedfilm orspl'ate and of X-radiation iscaused to move during the exthe relative movement necessary between theposure or between two separate exposures, the source of X-radiation andthe said body for the said grid being moved a direction at right purposeof presenting different aspects of the angles to the direction of the:grid strips and said body to said X-radiation is achieved bysubstantially parallel to the sensitized surface. moving said bodyduring the exposure or'between The grid consists essentially of a numberof two or more separate exposures.

narrow, substantially .parallel strips-of material According to anotherfeature of the present having'a high-degree of opacity to X -radiation,invention there is provided apparatus for makeaoh pair of adjacentstrips being separated by ing stereoscopic radiographs comprising a,eara space or medium of high transparency to rier for the body to besubjected tdX-radiation, X- radiation. The thickness of the aforesaid asupport "for a sensitized film or plate, a .grid grid is necessarilyconsiderable in comparison "located between said carrier and saidsupport, with the width of the strips of which it is coma source ofX-radi'ation, "means 'for moving said posed and in an endeavor to ensurethat the Carrier and s0 presenting difierent' sp p masking effectof-each strip will be substantially the said body to the X-radiation andmeans for uniform notwithstanding the different position causingrelative movement between said grid and which each strip occupies withrespect to the said supportfor the film or plate in a direction sourceof X-radiation it is desirable to use a at right angles to thelongitudinal axis of the grid-which is slightly curved in a senseresulting grid strips.

in all points on'an imaginary line bisecting the it is desirable thatthe planes of the film or surface of the grid at right-angles to thegrid plate and of the grid should be parallel orsubstrips lyingsubstantially on the eiroumzference stantially parallel to one anotherand it is line- -of a-circle of which the source of X-radiation isferred therefore to employ a curved support .f r the centre or to employa-grid which is fiat but :the film 'or plate in cases where thegrid'itself in'which thegrid strips or some of them are i'nis of thecurved kind. Such film or lat m 'clined about their transverse axes, thestrips near be enclosed in a cassette although in some=casesth'e'central axis of the grid'being normal to the itispreferable todispense with ac'assettesoas surface of said grid and the remainingstrips to enable the said film or plate ito' be disposed being inclinedtowards the said central axis to "closer to the grid, it being desirableto reduce an extent which increases progressively towards 40 thisdistance as much as possible'and in any theedges of the grid. Thesegrids however can event-to make such distance small in comparison onlywork e'fiiclentlywhen the source ofX-radi'awith that between the i -raytube and tne' gr i'd. 'tion is disposed in one particular position withIn the application of theipre'sent inventren to respect thereto andthere have therefore been the in'aking of radiographs of theparan'aapandifliculties in carrying out the suggested-methods oramagramtype the transparent or translucent of m kin r o pi r iosraphs wherein,as spaces ofthegrid are preferably narrower than above sta 1eXposureshave to be made with the the opaque strips but 'in :the case ofradicgraphs source of X-radiation in at least twodifferent of'theparallaxstereo'gram*type the'-said -transpositions. parent ortranslucent spaces and opaque strip Gneof the objects of the presentinvention is are preferably of equal width.

The aforesaid movement of the carrier for the body to be subjected toX-radiation is preferably of an angular nature. Thus for instance acarrier in the form of a cradle r platform may be caused to rock orpivot about an axis parallel to the grid strips, the resultant angularmovement of the body carried thereby then presenting different aspectsof said body to the X-radiation.

The aforesaid relative movement between the film or plate and the gridmay be attained by moving either or both of these parts but in generalit is preferable to provide for movement being imparted only to thegrid.

The aforesaid movement of the carrier and the movement of the grid orthe film or plate support are of course coordinated or synchronised inthe appropriate manner. Thus in the making of a radiographic parallaxpanoramagram the exposure may be a continuous one commencing andterminating respectively with the commencement and termination of themovement of the support or carrier for the body to be subjected toradiation or alternatively a number of separate exposures may be giveneach with said support or carrier in a different position, in both casesthe grid or the plate or film being caused to move through a distanceequal to the width of one opaque strip of the grid while the body isbeing caused to move between its two extreme positions. In this way thewhole of the sensitized surface of the film or plate is exposed and animage or succession of images of the parallax panoramagram type will beformed. After development the picture is viewed through an optical linedgrid having the same pitch as the radiographic grid and a stereoscopicview is obtained.

The procedure in the production of a radiographic parallax stereogram issimilar to that above described but only two exposures are necessary,spaced strips constituting one half of the sensitized surface of thefilm or plate being exposed during one exposure and the interveningstrips constitutin the other half of the sensitized surface beingexposed during the second exposure. The two exposures are in such casesmade whilst the object being subjected to X- radiation is stationary andproviding the second exposure is not made until the necessary movementof the object and of the grid or of the plate or film has been completedthere is no necessity to synchronize the movements.

In order that the present invention may be well understood certainembodiments thereof will now be described, by way of examples only, andwith reference to the accompanying drawings in which:

Figure 1 is a perspective view of one form of grid,

Figure 2 is a broken perspective view of another form of grid,

Figure 3 is a plan view of one form of grid mounting showing one mode ofimparting movement to the grid,

Figure 4 shows in broken perspective view one form of carrier for a bodyto be subjected to X- radiation and one mode of associating the gridtherewith.

Figure 5 is a diagrammatic view indicating the principles of theoperation of the apparatus shown in Figure 4, and

Figure 6 is a perspective View of another form of apparatus according tothe present invention.

Referring to Figure 1 of the drawings, the grid I is composed of anumber of strips 2 of lead or other material which is opaque toX-radiation with intervening strips of any suitable material such as aplastic which is transparent to X-radiation. The grid is of plane formand the sides of the opaque strips are so disposed that the angles whichsuch sides make with the place of the grid are equal to or substantiallyequal to the angles of incidence of the X-rays falling thereon, thesource of radiation being designated 3 in Figure 1. In this wayvariations in the masking effect at different parts of the grid areavoided.

Figure 2 shows another form of grid and in this embodiment uniformmasking is attained by imparting to the grid l a curvature which resultsin a line bisecting the grid strips lying on the circumference of acircle struck about the source of radiation as its centre.

The opaque strips of the grids shown in Figures 1 and 2 may be aboutfour times as wide as the intervening transparent strips if the grid isintended for use in making radiographs of the parallax panoramagram typebut for use in making radiographs of the parallax stereogram type thesaid opaque and transparent strips are preferably of equal width.

Referring now to Figure 3, a grid 5 is mounted in a frame 6 and thesides of such frame which extend longitudinally with respect to the gridstrips are parallel to one another but inclined with respect to suchstrips. The frame E is slidably supported in an outer frame 7 and thosesides of said frame "5 which are adjacent to the aforesaid inclinedsides of the frame 8 are correspondingiy inclined with the result thatas said inner frame 6 is moved along the outer one in a directionparallel to the grid strips a movement transversely with respect to saidstrips is also generated.

Springs 8, 8 are interposed between the end members of the frames 6 andl for urgin the frame E5 towards the base of the frame 7 as viewed inFigure 3 and the means for urging said inner frame in the oppositedirection consist of a cam or eccentric 53 mounted on a shaft If), thesaid shaft being driven by the worm wheel I! and worm l2 so that finecontrol can be exerted over the movement of the grid. The said worm i2may be out in or mounted on a control shaft l3 provided with anysuitable hand wheel or the like i l.

The range of sliding movement of the frame 6 and the inclination of therelevant parts of its supporting frame I are so chosen that the fullrange of movement will result in a transverse movement at least equal tothe width of one opaque strip of the grid and stops may be pro vided inorder to ensure that the range of movement will always be of the correctamount.

Figure 4 shows one form of apparatus including means for supporting aperson in a horizontal position whilst being subjected to X-radiation.In this construction the apparatus includes a cradle-like structurecomprising a curved carrier i5 capable of being rocked about alongitudinal axis. Said carrier is made of a plastic or other suitablematerial which is transparent to X-radiation. If desired frameworks suchas those designated l6 and i? may extend from said carrier, suchframeworks being made for example from a strong aluminum alloy. Ingeneral it is preferable to leave one side of the platform unobstructedbut frameworks of the above mentioned kind may be located on the otherthree sides.

The carrier i5 is supported for example resiliently by means of springsor the equivalent. In the example shown in Figure 4 springs are locatedbetween the carrier and the supporting arcades base 18; one ofthesprings on one side being designated I9- and the correspondingspr'ing onthe opposite side being designated 20. Positive stops areprovided forlimiting the extent to which the carrier l5 can rock in both directionsand the'springs on one side arestronger than the springs on the otherside so that the carrier normally tends to rock to its limiting positionin one direction Means are provided for positively rocking the aforesaidcarrier in a directionopposite to that in which it is rocked by thestronger springs, said means consisting inthis example of a wire 21which can be wound to a variable extent on a control shaft 22, saidcontrol shaft being provided'w'ith a ratchet wheel 2-3 with which a pawl24 cooperates so as normally to prevent reverse movement of the carrier.The shaft 22 is provided with a hand wheel or the like 25 and it will b''u'n'derstood that by winding said handle in a direction drawing thewire downwardly the carrier l5 can be rocked to its limiting position ina direction opposite to that in which it tends to move under theinfluence of its spring mounting and during this time the pawl andratchet mechanism prevents any inadvertent return movement of thecarrier although at the end of the desired movement the pawl 24 can bereleased whereupon movement of the carrier back to its initial limitingposition will be effected automatically under the influence of the abovementioned springs.

A grid assembly shown diagrammatically in Figure 4 and designated 25 ismounted on the base l8, such assembly being for instance similar tothat'described with reference to Figure 3 of the drawings and thecontrol shaft of such assembly preferably being formed by theabovementioned control shaft 22 of the carrier operating mechanism.

It is desirable that the grid of the aforesaid assembly 26 be flush orsubstantially flush with the upper surface of the base l8 and for thispurpose an opening is provided in the base for receiving such assembly.

In order to enable radiographs to be taken at Various pointslongitudinally along the carrier 35 aplurality of grid assemblies andtheir associated control gear may be located at intervals along the baseand may be operated simultaneously. In cases however where it is onlydesired to take one radiograph at a time but at various positions alongthe carrier the said grid assembly and control gear may be readilydetachable from the base 88 and applicable thereto at various points.Thus for instance a series of openings may be provided in the base forreceiving the grid assembly and the wire 2! of the control gear mayselectively engage one of a series of lugs such as the lugs 21 on therocking part of the apparatus.

The rocking movement of the carrier I5 is so coordinated with themovement of the grid in a direction at right angles to the grid stripsthat during the time taken for such grid to move through a distanceequal to the width of one opaque strip the platform completes therocking movement between its limiting positions assuming thatradiographs of the parallax panoramagram type are being made. If howeverradiographs of the parallax stereogram type are being madesynchronisation of these movements is not essential it being onlynecessary to ensure that eachof the two exposures is made when thecradle and'grid are in their appropriate limit positions.

Figure 5 indicates diagrammatically the rin-- 6. ci le involved in "usin'the apparatus illustrated in Figure 4. As will beseen from suchfisurethe sensitized film or plate Z8is'loca-ted'close tot-he grid 29.The carrier '31? which-istheequivalent of the carrier [5 ofli igure lis'als'o located as close as possib'leto the grid. Theca'rrier 30' whichin this example has upwardly inclined" side por tions is roc'kablefromthe position shown in full lines to the position shown indottedlines and designated 30. The body 3| to be subjected toX-radiation is located at the centre of the 'car= rier 30 and the source32 of X -rays' is also lo cated in alignment with the-centre of'the'carrier.

When the carrier 30' is in the position -shown in full lines the body 3l is in the positionalso shown in full lines and a line drawn normaltothe certtral axis of thecarrier "extends in the direction of the line33. When however the carrier is in'th'e position 30' the body 3 l=isinthe dottedline position designed 31" and aline'nor'mal' to the centralaxis of the carrier extends in the direetion of the line 34. Twodifferent aspects or a series of diiferent aspects of the body 3| are accordingly presented to the X-radiation.

It will thus be appreciated that the effectob+ tained is similar to thatwhich would result from moving the source of X-radiation from X to Xwhile the body remains stationary, but as the source of X-radiationisnot in fact moved the angles of incidence of therays remain incoincidence with the angles of inclination of the grid strips throughoutthe exposure-'inthe case of a parallax panoramagram or for each of theseparate exposures in the case of a'parallax stereogram.

Figure 6 shows a modified form of apparatus suitable for instance forsubjecting a person in a standing position to X-radiation. In thisembodiment the apparatus includes a base 35 on which is mounted a rotaryplatform 36and pillars 3'! extend upwardly from said base and carry agrid assembly 38 which may for instance be similar to the grid assemblyshown in Figure 3'. The grid assemblySB is preferably adjustablevertically along the pillars 3-Tand the rotary platform is preferablyadjustable horizontally e. g. between the positionshown in full linesand the position shown in dotted lines and designated 36'.

When the apparatus shown in Figure 6 is in use the person to beX-rayedstands on the platform 36, and the grid assembly 38 and'thesource of X-radiation 38 are adjusted to the appropriate positionsdependentupon the position of the part to be subjected to radiation.As'in the earlier described examples the grid is movable in a directionat right angles to the direction of the grid strips and the exposure isstarted with the platform and grid in one limiting position andterminated when such parts reach their other limiting position oralternatively separate exposures are made with-the parts in theirlimiting positions or in a series of positions dependent upon the typeof radiograph required.

In both of the above-examples the means for moving the grid and thecarrier or platform for the body to be subjected to X-radiation may beoperated manually but in general it is desirable for these to beoperated by means of a motor, e. g. an electric motor.

Whilst some embodiments of the present invention have been hereinbeforedescribed it'is to be understood that there may be various modificationswithout departing" from the scope of such invention. Thus-for examplethe carrier of platform for the body to b subjected to X- radiation maybe adapted to rotate or rock about an axis extending in any desireddirection, there may be provision for making radiographs simultaneouslyof various parts of the body and the grid and support may be caused toundergo the desired movements by various forms of mechanism other thanthose specifically described.

I claim:

1. A method of making stereoscopic radiographs wherein a grid isinterposed between the body to be subjected to X-radiation and asensitized surface on which the radiograph is to be made, said gridhaving a plurality of substantially parallel laterally spaced strips ofhigh opacity to X-radiation and a strip of high transparency in thespace between each pair of adjacent opaque strips, the said opaquestrips being at least as wide as the transparent strips, comprisingmoving the grid with respect to the sensitized surface in a directiontransversely with respect to the grid strips and through a distanceequal to the width of one of the opaque strips of the grid, the sourceof X-radiation being maintained in a stationary condition, and angularlymoving the body as a whole about an axis parallel to the longitudinalaxes of the grid strips so as to present different aspects of such bodyto radiation emanating from said source.

2. Apparatus for making stereoscopic radiographs comprising an angularlymovable carrier for supporting the body to be subjected to X- radiation,a support for a sensitized coating, a grid having a plurality ofsubstantially parallel laterally spaced strips of high opacity toX-radiation and a strip of high transparency to X-radiation in the spacebetween each pair or" adjacent opaque strips, the said opaque stripsbeing at least as wide as the transparent strips, a stationary source ofX radiation, means for moving the grid with respect to the sensitizedcoating in a plane parallel thereto through a distance equal to thewidth of one opaque strip of the grid and in a direction transverselywith respect to the grid strips, and means for moving said carrier andthereby positively moving a body located thereon in a directionsubstantially at right-angles to the longitudinal axes of the gridstrips so as to present different aspects of such body to radiationemanating from said source.

3. Apparatus as claimed in claim 2, wherein the sides of the grid stripsare inclined at angles substantially equal to the angles of incidence ofth X-rays falling adjacent thereto.

4. Apparatus as claimed in claim 2 wherein the grid is curved in a senseresulting in a line bisecting the grid at right angles to the gridstrips being substantially coincident with the arc of a circle struckabout the source of X-radiation as a center.

5. Apparatus as claimed in claim 2 wherein the carrier comprises acradle mounted for rocking movement about an axis parallel to thelongitudinal axes of the grid strips.

6. Apparatus as claimed in claim 2 wherein the carrier comprises arotary turntable mounted for rotation about an axis parallel to thelongitudinal axes of the grid strips.

7. Apparatus for making stereoscopic radiographs comprising a movablecarrier for th body to be subjected to X-radiation, a support for asensitized coating, a grid having a plurality of substantially parallellaterally spaced strips of high opacity to X-radiation and a strip ofhigh transparency to X-radiation in the space between each pair ofadjacent opaque strips, said opaque strips being at least as wide as thetransparent strips, a stationary source of X-radiation, means for movingthe grid with respect to the sensitized coating in a plane parallelthereto and through a distance equal to the width of one opaque strip ina direction transversely with respect to the grid strips, and means formoving said carrier and thereby moving a body located thereon in adirection substantially at rightangles to the longitudinal axes of saidgrid strips so as to present difierent aspects of such body to radiationemanating from said source, wherein said carrier is in the form of arockable cradle having spring suspension means disposed along its twosides, the suspension means on one side being stronger than those on theother side so that said cradle is normally rocked to one of its limitingpositions.

8. Apparatus as claimed in claim '7 wherein movement of the cradle in adirection opposite to that in which it is biased by the springsuspension means and movement of the grid are effected by common drivingmechanism.

9. Apparatus as claimed .in claim 2 wherein movement of the carrier andmovement of the grid are effected by common driving mechanism,

10. Apparatus for making stereoscopic radiographs comprising anangularly movable cradle for supporting the body to be subjected toX-radiation, a support for a sensitized coating, a grid having aplurality of substantially parallel laterally spaced strips of highopacity to X-radiation and a strip of high transparency to X-radiationin the space between each pair of adjacent opaque strips, the saidopaque strips being at least as wide as the transparent strips, astationary source of X-radiation, means for moving the grid with respectto the sensitized coatingin a plane parall l thereto through a distanceequal to the width of one opaque strip of the grid and in a directiontransversely With respect to the grid strips, and means for rocking saidcradle about an axis parallel to the longitudinal axes of the gridstrips.

11. Apparatus for making stereoscopic radiographs comprising a rotaryturntable for supporting the body to be subjected to X-radiation, asupport for a sensitized coating, a grid having a plurality ofsubstantially parallel laterally spaced strips of high opacity toX-radiation and a strip of high transparency to X-radiation in the spacebetween each pair of adjacent opaque strips, the said opaque stripsbeing at least as wide as the transparent strips, a stationary source ofX-radiation, means for moving the grid with respect to the sensitizedcoating in a plane parallel thereto through a distance equal to thewidth of one opaque strip of the grid and in a direction transverselywith respect to the grid strips, and means for rotating said turntableabout an axis parallel to the longitudinal axes of the grid strips.

12. Apparatus for making stereoscopic radiographs comprising a movablecarrier for the body to be subjected to X-radiation, a support for asensitized coating, a grid having a plurality of substantially parallellaterally spaced strips of high opacity to X-radiation and a strip ofhigh transparency to X-radiation in the space between each pair ofadjacent opaque strips, the said opaque strips being at least as wide asthe transparent strips, a stationary source of X-radiation, means formoving the grid with respect to the sensitized coating in a planeparallel thereto through a distance equal to the width of one opaquestrip of the grid and in a direction trans- UNITED STATES PATENTSversely with respect to the grid strips, and means Number Name Date formoving said carrier and thereby positively 758,117 Snook Apr. 26, 1904moving a body located thereon in a direction sub- 5 1,208,474 CaldwellDec. 12, 1916 stantially at right-angles to the longitudinal axes1,954,321 Kieffel' Apr. 1934 of the grid strips so as to presentdifferent as- 2,029,300 Arftsen Feb. 4, 1936 pects of such body toradiation emanating from 2,281,931 Frank May 5, 1942 said source, thesaid movement of the carrier 2,320,587 Gieringer June 1, 1943 and thesaid movement of the grid being efiected 10 FOREIGN PATENTS by commondriving mechamsm.

LESLIE PETER CLARENCE JACK DUDLEY. Number ry Date 490,299 Great BritainAug. 12, 1938 REFERENCES CITED The following references are of record inthe 15 file of this patent:

